A virtual system comprising several virtual machines (VMs) or virtual servers may be for example applied in a datacenter comprising one or more physical servers (PSs) hosting the VMs. Shutting down of such a virtual system, particularly the PSs of the system, is problematic due to possible dependencies of the VMs. A shut down without taking the dependencies of the VMs into account can increase the risk of startup issues like hardware failures and may require a check of the disks storing the operating systems of the PSs and the VMs.
The U.S. Pat. No. 8,438,563B2 relates to a VM management program which causes a computer device for causing arbitrary VMs among a plurality of VMs implemented on a physical machine such as, e.g., a host machine to cooperate with each other to execute a control process to execute a process for managing the plurality of VMs, a management server device, and a method for managing a VM. This patent also describes a VM halt process, which considers dependencies between VMs when a halt start command for a selected VM is received.